Denshi Jisho — Online Japanese dictionary

論 ろん 1: argument; discussion; dispute; controversy; discourse; debate;
2: theory; doctrine;
3: essay; treatise; comment
Noun 
ロング long
Common word, Na-adjective, Noun 
ロンド rondo
Noun, ita: 
論議 ろんぎ discussion; argument; debate
Common word, Noun, Suru verb, No-adjective 
論旨 ろんし point of an argument; drift of an argument
Common word, Noun 
論理 ろんり 1: logic;
2: (No-adjective) logical
Common word, Noun 
論語 ろんご the Analects of Confucius - one of the Four Books
Noun 
論破 ろんぱ defeating (winning) in an argument
Noun, Suru verb 
ロン毛 ロンげ long hair
Noun 
ロンジン Longines
Noun 
ロンジー lungi (Burmese clothing)
Noun 
ロンパリ walleyes (from London-Paris, i.e. "One eye looks at London, one eye looks at Paris"); squint; divergent strabismus
Noun, Colloquialism 
論外 ろんがい out of the question
Common word, Na-adjective, Noun, No-adjective 
論拠 ろんきょ grounds of an argument
Common word, Noun 
論告 ろんこく prosecutor's closing argument
Common word, Noun, Suru verb 
論者 ろんしゃ advocate
Common word, Noun 
論説 ろんせつ editorial; dissertation
Common word, Noun 
論戦 ろんせん verbal dispute
Common word, Noun, Suru verb 
論争 ろんそう controversy; dispute
Common word, Noun, Suru verb, No-adjective 
論点 ろんてん point in question (at issue)
Common word, Noun 
論文 ろんぶん thesis; essay; treatise; paper; article
Common word, Noun 
論客 ろんかく controversialist
Noun 
論詰 ろんきつ criticism
Noun, Suru verb 
論結 ろんけつ conclusion
Noun, Suru verb 
論考 ろんこう study (of something)
Noun, Suru verb 
論策 ろんさく (written) treatment of current events
Noun 

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